A consonant preceded by a vowel is doubled , if followed by a consonant.

Likewise , according to pauṣkarasādi , a mute preceded by l or v.

According to some teachers , the mute only.

Also a consonant that follows r.

In place , however , of second and fourth mutes , when followed by consonants , is put the preceding mute.

As also , in all cases , when they follow r.

And when l precedes.

Also the preceding mute is inserted before ch , khi , and bhuja , when these follow either a preposition , pātha eṣaḥ , ati , āti , dhāma , parama or bhūte.

After a surd spirant followed by a mute is inserted a first mute of the same position with the latter , as abhinidhāna.

According to plākṣi , when the following mute is surd.

But according to plākṣāyaṇa , on the contrary , when the following mute is a nasal.

A first mute followed by a spirant is changed into its corresponding aspirate.

According to bāḍabhikāra , when the following spirant is not of the same position with it.

Now for exceptons.

A consonant before a pause is not doubled ; nor r , visarjanīya , jihvāmūlīya , or upadhmānīya.

Nor a spirant , when followed by a vowel.

Or , according to plākṣi and plākṣāyaṇa , when followed by a first mute.

According to hārīta , a surd spirant is not doubled.

Nor h , when followed by r.

Nor a lingual mute , when followed by a dental.

Nor l nor a dental mute , when followed by y or v.

Nor the following.

A letter followed by one homogeneous with itself , or one of the same mute-series , is not duplicated.

Unless , indeed , it be a non-nasal followed by a nasal.

Now for the views of certain teachers.

A l is not doubled when followed by h , ś , or v.

Nor a mute that is followed by a mute.

Nor an original final that is followed by a consonant.

A grave following an acute becomes circumflex.

Even when consonants intervene.

Not , however , when an acute or circumflex follows.

Not so , according to āgniveśyāyana.

Some say not , in all cases.